1. Field of the Invention
The present invention relates to a dispenser of substances in liquid or paste form.
2. Description of the Related Art
Dispensers are already in existence that comprise, in particular, a cylinder of substance surmounted firstly by an endpiece provided with an internal evacuation duct and fitted, secondly, with means for extracting the substance, and provided with an exhaust valve.
In general, the substance is taken from the cylinder by means of a pump that possesses an admission valve which co-operates with the exhaust valve to define a chamber inside the body of the pump.
The chamber is suitable for being put initially into suction to suck in substance from the cylinder, and then under pressure to expel said substance to the outside.
Unfortunately, such dispensers are relatively complex and therefore fragile insofar as they are constituted by a large number of parts.
Consequently, they are relatively expensive, thereby making them unattractive for use with samples.
In addition. beneath the pump body, the substance must fill the volume of the cylinder completely so as to avoid bubbles of air appearing subsequently and leading to faulty operation by loss of priming. Under such conditions, the various component elements are difficult to assemble.